A known treatment for aneurysms, particularly intercranial berry aneurysms, utilizes a balloon to fill and occlude the aneurysm. In such procedures the interior of the aneurysm is entered through the use of a microcatheter, typically fed along a guide wire which allows navigation into the cerebral arteries and entry into a cranial aneurysm. A balloon is attached to the end of the microcatheter and introduced into the aneurysm. The balloon is inflated and detached within the aneurysm, where it is left to occlude the sac and neck while preserving blood flow in the parent artery.
U.S. Pat. No. 4,364,392 describes an occlusion balloon which is delivered via a catheter to the occlusion site. Upon delivery, the balloon is inflated with a suspension of small solid particles in a carrier liquid. The balloon is made porous so that the carrier liquid perfuses through the balloon wall, shrinking the balloon over the solid, incompressible particles. A ridge/groove fitting releases the balloon from the catheter upon application of a sufficient pulling force.
U.S. Pat. No. 4,402,319 describes a balloon catheter having a portion at the joint between the catheter and the balloon which is cuttable by torsion or by heating to allow the balloon to be released from the catheter and remain behind to embolize a vascular lesion. The balloon may be initially inflated using a first fluid containing a contrast media so that the balloon location may be confirmed and adjusted as needed, after which it is deflated to remove the first fluid. A catalyzed curable liquid is then injected into the balloon where it polymerizes to form a solid before the balloon body is detached from the catheter.
U.S. Pat. No. 4,819,637 describes a releasable occlusion balloon which includes a friction-fit catheter mounting and a one-way valve allowing the balloon to be filled with a non-solidifying liquid.
U.S. Pat. No. 5,191,921 and U.S. Pat. No. 5,779,672 describe releasable occlusion balloons which use a pair of self sealing one-way valves to allow passage of a guide wire through the balloon and to allow the balloon to be filled with a non-solidifying liquid.
Thrombogenic coil devices which may be delivered via a catheter to an occlusion site and left there are also known. Examples of such devices are described in U.S. Pat. No. 5,122,136, U.S. Pat. No. 5,350,397, U.S. Pat. No. 6,077,260, U.S. Pat. No. 6,083,220 and U.S. Pat. No. 6,123,714. Detachment mechanisms include electolytic corrosion of a metal member and a ball joint released by a pusher mechanism.
All patents, other publications or copending applications mentioned anywhere in this application are expressly incorporated herein by reference in their entirety.
The present invention pertains to an occlusion balloon, a filling method therefor, and an occlusion mass formed therefrom.
In one aspect the invention comprises a releasable occlusion balloon made of a material which is porous to aqueous media and/or non-viscous liquid and which is substantially non-porous to hydrophobic and/or viscous material. The balloon wall material is preferably highly distensible so that it can readily conform to the aneurysm at very low pressure inflation and without distention of the aneurysm. The balloon wall may be a hydrogel material. The balloon wall may be biodegradable or coated with a biodegradable material.
The balloon is initially located in the aneurysm and at least partially inflated with an aqueous inflation fluid. The aqueous inflation fluid suitably includes a contrast agent which allows the location of the balloon to be confirmed and adjusted as needed. Once the location is determined to be satisfactory, the aqueous inflation fluid is gradually displaced, without deflating the balloon, with a second liquid comprising a solidifying non-aqueous or viscous material. The aqueous material passes through the balloon wall and into the bloodstream. In this way the initial location of the balloon is maintained. When the aqueous inflation fluid has been fully displaced, the balloon may be further inflated with the second liquid, if necessary to fill the aneurysm. Upon solidification of the solidifying material, the balloon may be detached in conventional manner and the catheter withdrawn, leaving the balloon in place.
The solidifying material is preferably one in which solidification is initiated by contact with water or saline.